Heart failure with preserved left ventricular ejection fraction in non-obstructive coronary artery disease: clinical utility of heart rate variability

Aim. To evaluate the role of heart rate variability in the pathogenesis of chronic heart failure with preserved ejection fraction (HFpEF) in patients with non-obstructive coronary artery disease (CAD). Materials and methods. The cross-sectional study included 65 patients (55.4% were males) with non-obstructive CAD. Non-obstructive CAD (stenosis < 50%) was confirmed by coronary computed tomography angiography. Heart rate variability (HRV) was evaluated by 24-hour Holter monitoring; parameters of time series and spectral analysis were analyzed. Results. Depending on the presence of HFpEF, the patients were divided into 2 groups: group 1 (n = 48) included patients with HFpEF, and group 2 (n = 17) encompassed patients without it. In patients with HFpEF, a statistically significant decrease in the total HRV and parasympathetic effects on the heart rate, mainly at night, as well as increased activity of cerebral ergotropic systems were revealed. In group 1, the values of the time series analysis of HRV and QT dispersion based on the study of RR interval duration (SDANN and SDNNidx) had a significant direct relationship with the level of myocardial stress in diastole, the value of vascular resistance, and the E / e’ ratio. The cut-off values of SDNNidx and pNN50 were identified, that may be used as markers for early diagnosis of HFpEF. Conclusion. In patients with non-obstructive CAD and HFpEF, it is advisable to perform 24-hour Holter monitoring and assess HRV parameters by the time series analysis, which, compared with the spectral analysis, has a closer relationship with the characteristics of left ventricular diastolic function and afterload.